Using Fresnel reflections does save a bit on rendering time as less rays are fired compared to a material without it. Also you should have slightly more contrast and the diffuse colour coming through. No need to reduce the materials diffuse value as this can loose colour accuracy.. The colour/texture is always underneath the reflection layer.

Thanks. Yes, nothing signed and sealed yet but I'm in Edinburgh on Thursday to meet the builder and discuss the kitchen in more detail, so I'm certain we have it! Its probably my favourite project to date